OK I towed my Formula Ford for years with a single axle.
My 26ft sailboat's trailer is a single axle and at 3500lbs towing weight, I have towed it with a 150hp mini van. Sucked on mountians in Kentucky but was fine on the flats. I now tow it and 20ft race box trailer with a 4.7L v8 Tundra.
Now there are single axles and there are single axles. Axles are usually off the shelf units and are rated for specific weight loading. My boat has a 3500lbs axle, my race trailer has 2, 3500lbs axles so it is 7000lbs gross capability. Same trailer had a 5000lbs axle option (10000lbs goss)
So pay attention to the total trailer weight plus car and equip. weight and make sure the trailer and axles are rated for that. Position the car on the trailer so that the tounge weight is at the reccommended amount. once you find where the car should sit on the trailer, then install some front tire chaulks and front and rear tiedown rings. OK the car is too low for the front lip/dam to go over the caulks, paint marks on trailer where the front wheels should go and make the caulks removable with a bolt or 2.
On tires. Use 8 ply Trailer radials set at 60psi. (no car tires..trailer tires only) I have had problems on the Boat and Race trailers with cheap OEM crossply tires. 8 ply Radials also got rid of the sway on both trailers.